1. Field of the Invention
The present invention relates to the sport of competitive rowing, more particularly, but not exclusively to a variable pitch rowlock and a novel facility to accurately measure, if necessary, the forces generated from a single point in the rowlock.
2. Description of the Related Art
In competition rowing, in which performance largely depends on minute changes and the preparation of equipment, how the rowing force is transmitted from the individual to the blade of an oar is critical. Oarlocks that are currently in the market place, however, still present problems in terms of free play and the accurate location and support of the oar in the row-bed or gate.
In particular, current gate designs commonly include a fixed pitch which cannot be easily adjusted, thus resulting in the pitch typically being set at a compromised setting. This compromise is typically set to prevent the oar from getting stuck in the water at the end of the stroke, versus the oar washing out. Currently there is no way of setting the pitch to the optimal setting for all phases of the rowing stroke, often referred to as catch, drive, and exit in rowing terminology.
Some coaches or crews will attempt to lean the pin in or out by physically bending the pin so that the pitch in the middle of the stroke can be set differently to the catch or finish. This technique is very coarse and cumbersome and typically fails to provide the desired outcomes. It also deforms and damages the pin. There are some commercially available wedges to assist in leaning the pin over. An alternative method is to wedge a small coin or washer under one side of the pin before tightening up the retaining nut. Leaning the pin only provides 2 or 3 degrees of adjustment. Leaning the pin does not allow the pitch to be set independently at the catch and finish of the stroke.
In addition to the above, prior art gate designs do not lend themselves to measuring force because of primarily two reasons:                1. There is no way to decouple the force sensor from measuring the weight of the oar in the gate and separating the thrust of the oar being applied in a horizontal direction to the pin from the gravitational weight of the oar itself; and        2. Current pitch adjustment mechanisms have considerable free play resulting in inaccurate force measurements.        
Force measurements are currently determined either by measuring the force of the feet into the shoes or by measuring the load on the pin. There have also been attempts to measure the strain on the oar. Measuring the force on the shoes provides no reference to where in the stroke the pressure was applied, and this measurement is only accurate for the leg drive, not for the back swing or arms. Further, measuring the load on the pin, measures the combined weight of the oar with the force being applied. Although both techniques are used, neither provides an accurate measurement of force being applied to propel the boat in the forward direction, and neither method provides a reference to the angular position of the oar (Catch, Dive and Finish). Both techniques are also complicated to set up and calibrate and are only implemented by the true elites in the sport, for example the Australian Institute of Sport (AIS).
Some force measurement systems address the issue of free play by removing the pitch adjustment altogether, and locking it at 4 degrees. This is not acceptable for elite level rowers and as a result these systems are seldom left on the boat.
The disadvantages of the prior art can be summarised as follows:                Bending the pin provides no graduated adjustment of pitch across each phase of the rowing stroke e.g. catch, legs, back, arms, tap down.        No accurate and reliable way to adjust all gates in the boat to the same pitch profile.        Pitch can not be set independently at the catch and finish of the stroke.        The technique is not repeatable with any real accuracy.        Current force measurements do not truly reflect the propulsion to the boat.        Measuring from the feet or strain on the oar provides no angular reference to indicate where in the stroke the force was applied.        Without being able to accurately measure the force/angles and length of the stroke it is not possible to properly tune the pitch of the blade for optimum performance.        The same applies to setting oar lengths, inboard and outboard, and feet locations.        Pitch adjustment without accurate measurement would require guess work and would not result in maximum performance.        Current nylon pitch adjusters are loose fitting resulting in a large noise component in any force measurement taken on the pin.        
It is therefore an object of the invention to ameliorate some or all of the above disadvantages of the prior art by providing a novel and innovative variable pitch rowlock or to at least provide the public with a useful choice.